I can only get spark on Bayou 220 when starter is turning over but not engauging crank

Remove spark plug and try again. If still hard to pull then most likely it needs new a new recoil starter.

does pulling the start rope turn the engine over . make sure the tine drive is disconnected
if yes , the motor is not seized but the tines could be
if the motor will not fire ( check spark plug for spark it could be the coil or a short to ground in the ignition on/off switch wire

You say Pull rope mechanism is ok, How do you know that? Ive's seen them get the rope a little off and gets caught being wedged into a small clearance. Is the rope wearing? I bet if you take it apart put a new nylon rope and some wd-40 in rubbing surfaces including the ratchet area it will be good as new. Crank bearing has to get really bad to effect pull. How is the spark?

When you try to start the engine pulling on the rope, is it easier or harder to pull to turn over the engine? If easier there is internal damage as below, if harder there is internal damage as below. That cranking or grinding sound could be the rope starter or the clutch of the rope start. So when you have the cover off of the flywheel pull on the rope and see if it makes the sound you are hearing and check the clutch that threaded onto the the crank holding the flywheel in place see that it turns in freely in the opposite direction of the engine running.

You may have bent the crank, take the spark plug out, put the mower on it's side with the carburetor on the up side and turn the mower blade by hand and see if you can tell if there is a wobble. While you have the spark plug out, look in the plug hole while turning over the engine to see of the piston is moving up and down. Another possible problem the cam gear could be broken and the valves not opening and closing in time with the crank.

try tapping with a rubber mallet on top cover of PLastic wheel housing there is a clutch inside there that allows for free wheel after starting , sometimes these clutches get stuck dissengauged till you shock(mechanical) em back to engauge
also hairspray applied to pull rope (pulled out) help to prolong these for some time , my girlfriend showed me that one sometime back

If your engine does not turn over with the starter or pull rope, take spark plug out and see if the motor will turn over. If it will not turn over you may have a stuck piston. Was it running before?

check ht cap and lead is good. is power getting to coil. check fuel is getting in carb and tank tap aint blocked

Remove spark plug and observe condition. Fouled with oil, bad motor. With plug removed pull rope several times to blow out cylinder. Spray WD40 in spark plug hole, pull rope several times see if oil blows out. Spray a lot of starter fluid in spark plug hole, replace plug. Spray starter fluid in air cleaner area of carb, try to start. Replace spark plug, try to start. Ensure oil is full, all mowers have a low oil sensor now. 30w oil. Always use Stabile in gas.

Assuming the rope stays on the internal pulley, it is NORMAL for the rope to require great force at points in the cranking cycle (once per revolution of the crankshaft). These are the compression strokes and the force is MANY times the initial pulling force. If the rope returns easily, then the starter assembly is probably normal. It takes a strong arm and fast movement to start the enginess via pull rope. Some units have a compression release to ease this a bit.

If I understand what you are saying... The starter pulls smoothly with the starter cover removed or when installed and the plug removed (no compression or spark). If this is correct I think your saw's timing has slipped or maybe a defective decomp valve. Time to visit your neighborhood chainsaw seller/mechanic.HTH
Lou